Abstract: Objective To compare the corneal thickness and diopter stability after SMILE、FS-LASIK and T-PRK for correcting myopia. Design Retrospective cases series. Participants From January 2021 to July 2021,108 patients(108 right eyes) who underwent corneal refractive surgery in Zhengzhou Aier Eye Hospital. According to the accepted surgery, the patients were divided into SMILE（36 eyes）, FS-LASIK （36 eyes） and T-PRK（36 eyes）. Methods Apical corneal thickness (ACT) and spherical equivalent (SE) were reviewed preoperative, 2 weeks, 1 month, 3 months, 6 months and 1 year after surgery. The ACT and SE of one kind of surgery at different time and each time point were analyzed. Main Outcome Measures ACT, SE. Results Comparison of postoperative ACT: After SMILE the thinnest was 2 weeks, and the second was 1 month (all P＜0.05). After FS-LASIK, there were no significant differences between 1 month, 6 months with 3 months, but the thickness were gradually increased at other times(all P＜0.001). There were significant differences between 1 month and 3 months with other times after Trans-PRK (all P＜0.05) . The ACT became thicker in the early period after Trans-PRK, then became thinner, until stablily. Statistically significant differences of SMILE and Trans-PRK were thicker than FS-LASIK at any time (P＜0.05). Comparison of postoperative SE: Statistically significant differences of 2 weeks after SMILE was higher than 1 year (P=0.037). The diopter was unstable in the 1 month after FS-LASIK (all P＜0.05). There were significant differences between 1 month, 6 months with 1 year after Trans-PRK (all P=0.002). Statistically significant differences of SMILE was lower than FS-LASIK at 2 weeks (P=0.002). There was no statistical significance between the three surgery at other time. At 1 year after surgery,  SE within range ±0.50 D at SMILE, FS-LASIK and Trans-PRK group was 61%, 53% and 64%, respectively, and SE within range ±1.00 D was 93%, 89% and 89%, respectively. Conclusion The ACT all tended to be stable and slightly thickened after 3~6 months of the three refractive surgery. The corneal thickness of SMILE and Trans-PRK were thicker than FS-LASIK. The three refractive surgery all had a slight regression with time. Trans-PRK was preferred for low-moderate myopia or thin cornea, SMILE was preferred for moderate-high myopia, while FS-LASIK for high myopia or thin cornea should pay more attention to regression. (Ophthalmol CHN, 2023, 32: 496-501)

Key words: small incision lenticule extraction, femtosecond flap excimer laser in situ keratomileusis, smart pulse technology combined with excimer laser refractive keratectomy, apical corneal thickness, spherical equivalent